Divided impeller for blowers.



T. W. GREEN,

DIVIDED IMPELLBR FOR BLOWERS.

APPLICATION FILED AUG. 26, 1911.

Patented June 18, 1912.

2 SHEBTS-SHEBT 1.

IN VENTOR WITNESSES rm lmmlA PLANOGRAPH co., WASHlNC-T N. h. c.

T. W. GREEN.

DIVIDED IMPELLER FOR BLOWERS.

APPLIOATION FILED AUG. 26, 1911.

Patented June 18, 1912.

INVENTOR A 2 SHEETSSHEBT 2;

WITNESSES COLUMBIA PLANOGIAPH COJWASHINOTON, D. C.

TE ST an anion.

DIVIDED IMPELLER FOR BLOWERS.

Specification of Letters Patent.

Patented June 18, 1912.

Application filed. August 26, 1911. Serial No. 646,110.

To all whom, it may concern:

Be it known that I, THOMAS IV. GREEN, a citizen of the United States, and a resident of Philadelphia, Pennsylvania, have invented a certain new and useful Divided Impeller for Blowers, of which the following is a specification.

The purpose of my invent-ion is to build up an impeller of separable parts and to lock the parts against displacement.

A further purpose of my invention is to provide for employment of pressed sheet metal in impeller construction, thus very much reducing the cost as well as the weight.

A further purpose of my invention is to maintain existing waist dimensions in impeller construction while enlarging the shaft sect-ion.

A further purpose of my invention is to use a shaft which does not require machining, preferably square and of considerable size, within the waist of an impeller without unduly enlarging the width of the waist.

A further purpose of my invention is to interlock impeller parts so that they may retain each other against radial and tangential movement.

A further purpose of my invention is to provide for end sealing of impellers in pro portion to the pressure of the fluid being pumped.

I have preferred to illustrate my invention by the practical, efficient and relatively inexpensive forms thereof seen in the drawings.

Figure 1 is a transverse section of an impeller and cylinder embodying my invention. Fig. 2 is a section taken upon line cc-zc of Fig. 1. Fig. 3 is a sectional view of one half of an impeller. Fig. 4 is a section upon the line yy of Fig. 3. Fig. 5 is an end elevation of a modified form of impeller. Fig. 6 is a broken top plan view of Fig. 5. Fig. 7 is a broken side elevation of Fig. 5. 1

Similar numerals of reference indicate like parts in the drawings.

The impellers used in this type of blower or pump sometimes weigh tons. The distance between centers and, hence, the size of cylinder required for the same pumping capacity, is directly affected by the waistthickness and this must, in some instances, be deliberately enlarged to provide for proper shaft support. At the same time the considerable radius and great length of the blades makes reduction in their thickness quite desirable. In the large castings required a slight warping will considerably reduce the effectiveness of the blades, and the wear upon the bearings which results from the great weight of therevolving parts is destructive. These various objections are reduced by my construction which lightens the weight, makes it possible to use a larger shaft and removes the necessity for machine finish of the shaft.

1 is a cylinder having semi-cylindrical ends 2, 3 within which two like parts revolve about shafts 4, 5 to cause blades 6, 7 8, 9 of the two impellers to cooperate in turn, each blade sealing against a portion of the other impeller lying between its two blades. I have shown the sealing surfaces as limiting the sides of the waists and as approximately radial at 10, the radii being preferably in quadrant position.

In the form shown in Figs. 1, 2 and 3, I have preferred to make the impellers of pressed metal, in two duplicate parts or halves, making each half of the impeller i11- clude adjoining sides of the two blades. The blade parts 11 and 12 would thus form part of the same impeller half, as would, respectively, l3 and 14, 15 and 16, 17 and 18. Upon each part I form transverse flanges 19 at the ends, axially, so that the axial length of the impeller parts may be short for any total length required and the individual lengths may be secured to each other by any suitable fastening, as 20. This reduces the length of material that must be handled at one time and the size of dies required. The flanges are also quite effective in strengthening and stiffening the structure.

For the triple purpose of getting as large a shaft as possible, securing the greatest turning movement of the shaft against the blades and avoiding the necessity for machine finish of the shaft 21, I make it square at 22, in which section it may be secured in exact sizes of preferably cold-rolled material.

The connection between opposite impeller parts is formed so as to surround the square of the shaft upon three sides. The construction shown fits the shaft snugly for approximately half the thickness of each face of the shaft toward the belled blades, as at 23, on that half of the shaft farthest from the two belled portions and conforms nearly to the shape of the shaft at 24 upon that side of the waist of the impeller farthest from the two blade portions thus connected. In order that the waist may be more accurately shaped, I prefer to depart a little from the exact shaping of the metal to the shaft at the points 25.

The portions 26 connecting the sides, as 17, 18, with the parts 23, conform generally to the shape of the shaft but are offset from it at the approximate center, as at 27, so as to accommodate the corresponding parts 23 of the other half of the impeller between them and the shaft. The two impeller parts are cut away longitudinally, removing about half the portion 27 of each. The cuts are all from the same end so that, when the two parts which form a complete impeller length are placed opposite, the solid part of each shall correspond to the out part of the other. They can then be slid endwise, one upon the other, until the belled ends register, when the parts 11-13, 1214, 15-17, 16-18 are secured by rivets or other suitable means through substantially radial flanges 28, preferably with a sealing material 29 between them. I prefer also to rivet a stiffening angle 30 against the flanges in proximity to the waist line, forming this angle to agree with the inner contour of the belled ends and securing it, as well as the split impeller parts, to the shaft by bolts 31.

It will thus be seen that the two impeller blade parts upon the same side of the impeller are integral and are connected by a stirrup or loop which fits that half of the shaft farthest from it and which leaves room between it and the shaft for another stirrup or loop, uniting the corresponding pair of blade parts which form the remainder of the impeller.

It will also be apparentthat these impeller units are capable of insertion and withdrawal longitudinally only, and are stiff-- ened by the shaft and by the flanges through which they are united to adjoining sections. They are further stiffened at their points of greatest strain to maintain the accurate positioning of the waist sealing parts by angles or other corresponding means. The corners of the square shaft thus become effective as keys to insure rotation of the parts and each half of the structure locks the other against radial as well as tangential displacement.

In the form shown in Figs. 5, 6 and 7 a cast form of divided impeller structure is illustrated, having the same characteristic of longitudinal division so that the two blade parts'adjoining thesame side of the waist are integral in each case and are united at the waist about the shaft and by bolts or rivets at the ends to form a rigid entity.

In this structure, I show blade parts 32,

33 as comprising one integral part, with the connecting waist portion 34 and ribs or flanges 35, 36 which partly inclose the shaft. This entity cooperates with a corresponding entity embracing blade parts 37 38, Waist part 39 and ribs or flanges 40, 41, to make up the entire blade. The ends are provided with inwardly directed flanges 42 which are united by means of any suitable bolts or rivets 43 and may be made to hold packing 44 in place within any suitable groove 45. Each rib or flange 35, 36 is preferably transversely extended to cover a much larger portion of the shaft throughout half of the section length than through the remainder thereof, and the ribs 40, 41 are correspondingly extended, so that in the reverse position of the second half they appear to be reversely extended throughout half the section length. The greater extension of each flange upon one half thus corresponds in position to the lesser extension of the cooperating flange upon the other impeller half and gives a much greater leverage of the square shaft upon each of the blade portions for that half of the blade length throughout which the ribs or flanges are extended. If these transverse flange extensions alternate to place the greater extension of one flange opposite the lesser extension of the other upon the same impeller half, the two halves may be made exact duplicates. The two sections are bolted or otherwise secured to the shaft as at 46, and to each other, as at 47. I illustrate in this form of my invention an end sealing structure in which I make use of an opening 48 in the blade ahead of the main seal 44, in the direction of rotation as indicated by arrow 49. This opening communicates with the recess 45 under the seal 44, to press the seal outwardly, and preferably the same opening communicates air pressure through passage 50 to the rear 51 of a seal 52 projecting through a groove 53 to each axial end of the blade, which will be the end of each end section if the longitudinal sectioning of my other forms be applied to this construction. Stop 53 normally holds the seal from end movement.

The-division of the cast impeller is of great advantage in casting, in machining and in the ultimate product attained. In the casting, it is possible to mold it in green sand without coring, greatly reducing the expense and bringing itwithinthe capabilities of less skilled molders. The molding machine becomes then not merely possible, but of easy application. It can be handled by foundries having a smaller capacity. The convex sides of the belled or blade portions can invariably be placed down, where the metal poured is substantially free from sponginess and blow-holes. There is less distortion and each half can be finished separately to balance it. In casting the entire impeller a large proportion of the castings has been lost through sponginess and blow-holes in one of the belled sides. The substantial elimination of these difficulties avoids also the excessive allowance for finish upon the castings which has been necessary.

In machining, the shaft section can be milled to size and one or any number of sections can be quickly and accurately lined up on a milling machine or planer by setting them upon the shaft, greatly reducing the labor and the chance for error. The division longitudinally of the blades and the sectioning of the length both tend to bring the machine work within the reach of shops having but small equipment.

It will be seen that both the pressed anc the cast forms, in addition to their structural advantages and ease of application to the shaft laterally, reduce the weight and cost, increase the shaft hold and permissible size of the shaft and bring the construction within the range of plants having small capacity and equipment.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is 1. In a device of the character stated, in combination, a polygonal shaft, a pair of duplicate impeller halves, each flanged radially at its ends and extended laterally near the middle to overlap the other for a portion of the width of the shaft, means for securing the flanges together and means for securing the halves to the shaft.

2. In a device of the character stated, in combination, two pairs of impeller blade halves, the two of each pair being upon the same side of the impeller, a polygonal shaft and a connection between the impeller blade halves of each pair, said connection lying in contact with the farther portion of the shaft, being that portion lying directly between the halves of the other pair.

3. In a device of the character stated, in combination, a shaft, a pair of duplicate substantially radiallydivided impeller halves, one of each pair extending into and being overlapped by the other in proximity to the shaft and a connection bet-ween th'e halves where they overlap.

4. In a device of the character stated, in combination, a square shaft and longitudinally divided impeller parts, each, comprising halves of impeller blades upon the same side of the impeller and an intermediate part forming part of the waist between the other halves, each intermediate part making contact with three sides of the shaft.

5. In a device of the character stated, in combination, two impeller parts divided radially, longitudinally of the wings, each part carrying the wing halves for one side of the impeller and the shaft-engaging member for the opposite side of the impeller, and a shaft embraced by the two parts when fitted together.

'6. In a device of the character stated, in combination, a polygonal shaft and longitudinally divided interlocking impeller halves, one of said impeller halves conforming to approximately one half of the periphery of the shaft and the other impeller half conforming to approximately the opposite half of the shafts periphery, each extending into the body of the other beyond that axial plane of the shaft determined by the general division plane of the halves.

7 In a device of the character stated, in combination, two shaft-engaging central impeller sections, together embracing the shaft and preventing its independent rotation by their grip, means for holding them together, a non-circular shaft embraced by the sections, and impeller-blade halves extending divergently from the central sections and uniting to make up two wings each comprising halves from different central sec tions.

8. In a device of the character stated, in combination,longitudinally divided impeller members each comprising portions of both blades and part of the intermediate waist for one side of the impeller and a connection forming a portion of the waist for the opposite side of the impeller.

9. In a device of the character stated, in combination, a shaft, longitudinally divided interfitting impeller parts, each embodying one side of each of the impeller blades and having a connection passing about the opposite side of the shaft therefrom, and means for securing the portions to the shaft and to each other.

10. In a device of the character stated, in

combination, a shaft, impeller halves, each embodying a portion of each impeller blade, the port-ions being on the same side of the impeller, and a yoke uniting the impeller blade portions of the same halves conforming approximately to the half of the shaft farthest from these blade portions and interfitting wit-h the yoke of the opposite section upon the nearer part of the shaft and means for securing the two yokes to the shaft.

11. In a device of the character stated, a shaft, two shaft-engaging central impeller sections, each including part of an impeller waist, directed toward the other in contact with the shaft for a portion of the shaft periphery, diverged and slotted axially for a portion of its length to pass the other and continued, in substantial contact with the other, to the opposite impeller waist, in combination with an impeller-blade-half extension from each terminal of each cent-ral section united at the ends to form impeller blades from halves extended from different With the middle of the blade, means for 10 sections. securing the halves together near the ex- 12. In a device of the character stated, an tremity of the blade and means inserted impeller shaft, a pair of impeller halves, tofrom Within the blade for securing the 15 gether forming an impeller blade, divided halves t0 the shaft.

mainly longitudinally of the blade and each THOMAS W. GREEN. extended into the body of the other half WVitnesses:

beyond that axial plane through the im- VVILLIAM S'rEELL JACKSON,

peller shaft defined by a shaft radius in line i HELEN I. KAUFFMANL Copies of this patent may be obtained for five cents each, by addressing the "Commissioner of Patents,

Washington, D. G. 

